Codes 171 and 174, warning chime?

DEVELDOG

MEMBER
2005 FORD F-150
5.4L
V8
2WD
AUTOMATIC
250,000 MILES

When I start my truck after about a minute a warning chime goes off. Seat belts are on, and the doors are closed. I turn off the ignition and start truck again the warning chime doesn't do it after the second start up? At first, I thought it was maybe a seatbelt malfunction, so I unplugged them. No good still does it. Engine light on and codes 171 and 174 came up but I wouldn't think that would have anything to do with the warning chime. This has me puzzled.

5 Replies

STEVE W.

MECHANIC
13,573 POSTS

Likely it's the chime to tell you to look at the dash because the CEL is on. Common way they try to get your attention. I would get the issue causing the light to be on repaired as driving a vehicle with a lean mix on both banks of the engine can cause the engine to run hot in the cylinders and damage the engine. A common cause is a vacuum leak or a bad intake gasket.

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Friday, December 15th, 2023 AT 3:40 PM

DEVELDOG

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4 POSTS

The chime just comes on a minute after I start my truck. I turn my truck off. Restart it. And it doesn't do the chime. The check engine light came on a week ago. The chime thing has been going on for 6 weeks. I've stopped driving it until I find the code problem. The truck is still driving Great. Last time I took it out.

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Saturday, December 16th, 2023 AT 8:54 AM

STEVE W.

MECHANIC
13,573 POSTS

Okay, there are a few systems that can chime. When you turn the key on and the bulbs light up, does the air bag light work? You say it runs okay, any transmission issues? Check the washer fluid as well as coolant and brake fluid. If those all check out then I would pull all the codes, it's possible that a system is having an issue but not setting a code that turns on the light and is only triggering the chime. A full system scan may show it.

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Saturday, December 16th, 2023 AT 11:13 AM

DEVELDOG

MEMBER
4 POSTS

I haven't been able to find any vacuum leaks under the hood. Is there a vacuum to the fuel tank or transmission under the truck? All my fluids are right where they need to be. I changed the fuel filter 2 years ago. I changed the oil and filter about 6 months ago. And put new brake pads on the front and rear a year ago. I had a plug misfire on the #1 cylinder, so I just replaced all the plugs and ignition coils a year ago. And that was real fun. I only had 2 plugs break. Bought a plug puller for the 5.4. For $125.00. Totally worth it.

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Saturday, December 16th, 2023 AT 12:09 PM

STEVE W.

MECHANIC
13,573 POSTS

There is the EVAP purge line that runs back to the tank, if it was stuck open it might cause lean codes. If you have a scan tool that can read live data you can test the valve without a lot of fuss. You would run the engine and watch the fuel trims. Then you block the EVAP line and see if the fuel trims change to compensate for the lack of air from the leak. If you don't have a scan tool that can do that there are some reasonable ones out there or look at FORScan and the proper dongle. The windows version is as powerful as the OE tool and is much less money.

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